Fuel cell system

Abstract

To provide a fuel cell system capable of optimizing fuel of a fuel cell.SOLUTION: A fuel-cell system 1 includes an ECU 9. The ECU 9 calculates, in a predetermined period, a mean value obtained by averaging instantaneous output values sequentially requested by a fuel-cell system 1 in a mean calculation time section in which the fuel-cell system 1 is operated, sequentially sets, every time the mean value is calculated, the mean value as an output value to be output by the fuel-cell 2 until a next predetermined period, adds a predetermined period to the mean calculation time section every time the mean value is calculated, and causes difference between an instantaneous output value of the fuel cell system 1 and an output value of the fuel cell 2 to be compensated by the output value by discharge of a battery 6.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a fuel cell system.

Background Art

[0002] Patent Document 1 discloses a technique for calculating the time average value of an electrical load value that is the target of power management of a moving body, and calculating the power generation amount of a fuel cell from the time average value of this electrical load value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in Patent Document 1, the time for calculating the average value of the electrical load value (hereinafter simply referred to as the "calculation time") may not be optimal, and the fuel may not be optimal. For example, in Patent Document 1, when the period of the calculation time is too short, the output of the fuel cell also increases and decreases in response to fluctuations in the electrical load in a short period of time, so the fuel is not optimal. On the other hand, when the period of the calculation time is long, there is a problem that when the average electrical load and the output of the fuel cell are large, the required power cannot be obtained.

[0005] The present disclosure has been made in view of the above, and an object thereof is to provide a fuel cell system that can optimize the fuel of the fuel cell.

Means for Solving the Problems

[0006] To solve the above-mentioned problems and achieve the objective, the fuel cell system according to the present disclosure comprises a fuel cell that generates electricity using fuel, a battery capable of charging and discharging electricity, a drive source that is driven using electricity output from at least one of the fuel cell and the battery, and a processor that controls the electricity output by each of the fuel cell and the battery, wherein the processor calculates an average value at a predetermined period by averaging the instantaneous output values ​​sequentially requested by the fuel cell system over an average calculation time interval in which the fuel cell system is in operation, sets the average value to be output by the fuel cell up to the next predetermined period each time the average value is calculated, adds the predetermined period to the average calculation time interval each time the average value is calculated, and compensates for the difference between the instantaneous output value and the output value with the output value due to the discharge of the battery. [Effects of the Invention]

[0007] According to this disclosure, the fuel for the fuel cell can be optimized, which has the effect of being the best possible. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing a vehicle equipped with a fuel cell system according to Embodiment 1. [Figure 2] Figure 2 shows the relationship between the output and thermal efficiency of the fuel cell according to Embodiment 1. [Figure 3] Figure 3 shows the relationship between instantaneous output value and time in the fuel cell system according to Embodiment 1. [Figure 4] Figure 4 shows the relationship between instantaneous output value, fuel cell, battery, and time in the fuel cell system according to Embodiment 1. [Figure 5] Figure 5 shows the relationship between instantaneous output value, fuel cell, motor, battery, and time in the fuel cell system according to Embodiment 1. [Figure 6] Figure 6 is a diagram showing an overview of the processing of the fuel cell system according to Embodiment 1. [Figure 7]Figure 7 is a flowchart showing an overview of the processes performed by the fuel cell system according to Embodiment 2. [Figure 8] Figure 8 is a schematic diagram showing the transition conditions in modes 1 to 3 executed by the fuel cell system according to Embodiment 2. [Figure 9] Figure 9 shows the relationship between the output value of the fuel cell and the battery output value (discharge), the input (charge) of the battery 6, and the time, according to Embodiment 2. [Modes for carrying out the invention]

[0009] Hereinafter, a vehicle equipped with a fuel cell system according to an embodiment of the present disclosure will be described with reference to the drawings. However, the present disclosure is not limited to the following embodiments. Furthermore, in the following description, the same parts will be denoted by the same reference numerals.

[0010] (Embodiment 1) [Vehicle Overview] Figure 1 is a schematic diagram showing a vehicle equipped with a fuel cell system according to Embodiment 1. The fuel cell system 1 shown in Figure 1 comprises a fuel cell 2, a boost converter 3 (hereinafter simply referred to as "FDC3"), a motor 4, an inverter 5 (INV), a battery 6, a first detection unit 7, a second detection unit 8, and an ECU (Electronic Control Unit) 9. The fuel cell system 1 is mounted on a vehicle 100.

[0011] Vehicle 100 is a fuel cell electric vehicle (FCEV) that drives a motor 4 using electricity generated by a fuel cell 2, and runs using the power output from the motor 4.

[0012] The fuel cell system 1 is electrically connected to a fuel cell 2 and an FDC 3. The fuel cell 2 has multiple cells (not shown). Under the control of the ECU 9, the fuel cell 2 generates electricity using hydrogen supplied from a hydrogen tank (not shown).

[0013] FDC3 is a boost converter that, under the control of ECU9, boosts the voltage of the power generated by fuel cell 2 and outputs it. FDC3 is a DC / DC converter for fuel cells.

[0014] Motor 4 is a drive motor and a motor-generator that functions as both an electric motor and a generator. This motor 4 is composed of an AC motor. Motor 4 is electrically connected to the fuel cell 2 and FDC 3 and the battery 6 via an inverter 5. Under the control of the ECU 9, motor 4 is driven by power output from the fuel cell 2 supplied via the inverter 5. Also, under the control of the ECU 9, motor 4 is driven by power output from the battery 6 supplied to motor 4 via the inverter 5.

[0015] The inverter 5 is a power conversion device that, under the control of the ECU 9, converts DC power into AC power and supplies it to the motor 4. The inverter 5 is electrically connected to the motor 4, the FDC 3, and the battery 6.

[0016] Battery 6 is a DC power source and consists of a secondary battery that stores power to supply to motor 4. Under the control of ECU 9, battery 6 supplies power to motor 4 when fuel cell 2 cannot generate sufficient power, and stores the power generated by motor 4 during regeneration. In this case, the power output from battery 6 is supplied to motor 4 via inverter 5, and the power generated by motor 4 is supplied to battery 6 via inverter 5. Battery 6 is also electrically connected to fuel cell 2.

[0017] The first detection unit 7 detects the temperature of the battery 6 and outputs the detection result to the ECU 9. The first detection unit 7 is configured using a temperature sensor or the like.

[0018] The second detection unit 8 detects the State of Charge (SOC), current value, and voltage value of the battery 6, and outputs the detection results to the ECU 9. The second detection unit 8 is electrically connected in parallel and series to the connecting line between the battery 6 and the inverter 5, and detects the SOC, current value, and voltage value of the battery 6, and outputs the detection results to the ECU 9.

[0019] The ECU9 is implemented using a hardware-based processor. Its hard disk includes, for example, memory, a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field-Programmable Gate Array), and a GPU (Graphics Processing Unit). The ECU9 controls each component of the fuel cell system 1. The ECU9 drives the motor based on the detection result of a third detection unit 10 that detects the access opening. The ECU9 also controls power generation by the fuel cell 2 and charging / discharging of the battery 6. The ECU9 calculates an average value at a predetermined interval, averaging the instantaneous output values ​​sequentially requested by the fuel cell system 1 over the average calculation time interval in which the fuel cell system 1 is operating. Each time this average value is calculated, the ECU9 sequentially sets the average value to the output value A that the fuel cell will output up to the next predetermined cycle. Subsequently, each time the average value is calculated, the ECU9 adds a predetermined cycle to the average calculation time interval and compensates for the difference between the instantaneous output value of the fuel cell system 1 and the output value A of the fuel cell 2 with the output value due to the discharge of the battery 6.

[0020] [Summary of instantaneous power output values ​​from fuel cell systems] Next, we will explain the overview of the instantaneous output values ​​in fuel cell system 1. Figure 2 shows the relationship between the output and thermal efficiency of fuel cell 2.

[0021] As shown by curve L1 in Figure 2, the thermal efficiency of the fuel cell 2 decreases as it is operated under higher loads. Therefore, the characteristic of the fuel cell 2 is generally an upward-convex curve (hereinafter simply referred to as "point 1").

[0022] Figure 3 shows the relationship between instantaneous power output and time in the fuel cell system 1. In Figure 3, the horizontal axis represents time, and the vertical axis represents the power output (instantaneous power output) required by the fuel cell system 1. Also in Figure 3, curve P represents the instantaneous power output required by the fuel cell system 1, and straight line P ave_total This shows the average output value obtained by averaging the instantaneous output values ​​required by the fuel cell system 1 over the operating time t (average calculation time interval) of the fuel cell system 1.

[0023] Fuel cell 2 aims to achieve the best thermal efficiency and fuel economy by reducing the maximum output value from point 1. Furthermore, curve P and straight line P in Figure 3. ave_total As shown, the instantaneous output value and the average output value are the same amount of work done at time t. Therefore, when the fuel cell system 1 achieves the same amount of work, point 1 and the curve P and line P in Figure 3 ave_total As shown, when the output value of fuel cell 2 is denoted as output value A, output value A = average output value (straight line P ave_total This occurs when ) is kept constant (hereinafter simply referred to as "Point 2").

[0024] Figure 4 shows the relationship between the instantaneous output value, fuel cell 2, battery 6, and time in fuel cell system 1. In Figure 4, region B1 represents the discharge power of battery 6 and indicates the amount of work compensated by battery 6, region B2 represents the amount of charge of battery 6 by fuel cell 2, and region B3 represents the output value A of fuel cell 2.

[0025] As shown in Figure 4, when the fuel cell system 1 ignores losses such as charging and discharging of the battery 6, the output value A of the fuel cell 2 is equal to the average output value P. ave_total In this case, the amount of work compensated by battery 6 in region B1 and the amount of charge of battery 6 by fuel cell 2 in region B2 are the same. Therefore, in order to achieve point 2, the fuel cell system 1 sets the instantaneous output value P of the fuel cell system 1 and the output value A (average output value P) of fuel cell 2. ave_total The difference between these values ​​is compensated for by the output value of battery 6 (hereinafter simply referred to as "point 3").

[0026] That is, the ECU 9 controls the fuel cell 2 and the battery 6 so as to supplement the difference between the instantaneous output value of the fuel cell system 1 and the output value of the fuel cell 2 with the output value by the discharge of the battery 6.

[0027] FIG. 5 is a diagram showing the relationship between the instantaneous output value, the fuel cell 2, the motor 4, the battery 6, and time in the fuel cell system 1. In FIG. 5, the region B3 indicates the output value A of the fuel cell 2, the region B4 is the discharge power of the battery 6 and indicates the amount of work by the battery 6, and the region B5 indicates the charge amount of the battery 6 by the output value of the fuel cell 2 and the regenerative energy of the motor 4.

[0028] As shown in FIG. 5, the motor 4 is responsible for the work of moving the vehicle 100. Therefore, the instantaneous output value P of the fuel cell system 1 can also be replaced with the output value M of the motor 4.

[0029] As shown in FIG. 5, when the motor 4 regenerates and the charging side of the battery 6 is represented by a negative value, the best thermal efficiency and fuel consumption are achieved when the output value A = M of the fuel cell 2 ave_total is constant. Furthermore, in the fuel cell system 1, when the output value A of the fuel cell 2 is the average output value M of the motor 4 ave_total the amount of work in the region B4 and the charge amount in the region B5 are the same. Therefore, the fuel cell system 1 may supplement the difference between the instantaneous output value of the motor 4 and the output value A of the fuel cell 2 with the output value of the battery 6 (hereinafter simply referred to as "point 3_1").

[0030] However, in the fuel cell system 1, before driving, each of the instantaneous output value P or the output value M of the motor 4 and the time t which is the driving time of the vehicle 百 (the operating time during which the fuel cell system 1 operates) is unknown. Therefore, the average output value P of the fuel cell system 1 ave_total is also unknown, and the output value A of the fuel cell 2 cannot be set. In particular, when the vehicle 100 is a commercial vehicle, the output value M of the motor 4 changes greatly when the loading amount is different.

[0031] Therefore, the ECU 9 calculates an average value at a predetermined interval, which is the average of the instantaneous output values ​​sequentially requested by the fuel cell system 1 over the average calculation time interval in which the fuel cell system 1 is operating. Each time this average value is calculated, the ECU 9 sequentially sets the average value to the output value A that the fuel cell will output up to the next predetermined period. Subsequently, each time the average value is calculated, the ECU 9 adds a predetermined period to the average calculation time interval and compensates for the difference between the instantaneous output value of the fuel cell system 1 and the output value A of the fuel cell 2 with the output value due to the discharge of the battery 6.

[0032] [Processing by fuel cell system 1] Next, the processing performed by the fuel cell system 1 will be explained. Figure 6 is a diagram illustrating the overview of the processing performed by the fuel cell system 1. In Figure 6, the upper section shows the relationship between the required output of the fuel cell system 1 and time, and the lower section shows the relationship between the target FC output value (exponent) of the fuel cell 2 and time (exponent). Note that in Figure 6, the time in the upper section and the time in the lower section correspond to each other. Furthermore, in Figure 6, the output value A is used as the output value of the fuel cell 2. _0 The explanation will be given assuming that this is the initial value.

[0033] As shown in Figure 6, the ECU 9 first calculates the instantaneous output value P of the fuel cell system 1 over a predetermined periodic average calculation time interval t _0 ~t _n The average output value P is averaged using this method. ave_n The average calculation time interval t is obtained by adding the time of the next period. _n ~t _n+1 The target output value A of fuel cell 2 at this time. _n Let's assume that.

[0034] Specifically, as shown in Figure 6, the ECU 9 calculates the average of the instantaneous output value P of the fuel cell system 1 over a time interval t _0 ~t _1 The average output value P is averaged using this method. ave_1 The next period is the average calculation time interval t. _n ~t _2 The target output value A of fuel cell 2 at this time. _1 The ECU9 calculates and sets the output value of the fuel cell 2 to output value A. _1The power generation of fuel cell 2 is controlled to achieve the following.

[0035] Next, ECU9 calculates the average time interval t by adding the next cycle. _0 ~t _n+1 The average output value P is averaged using this method. ave_n+1 The next period is the average calculation time interval t. _n+1 ~t _n+2 The target output value A of fuel cell 2 at this time. _n+1 Let's assume that.

[0036] Specifically, as shown in Figure 6, the ECU9 calculates the average time interval t by adding the next period. _0 ~t _2 The average output value P is averaged using this method. ave_2 The next period is the average calculation time interval t. _2 ~t _3 The target output value A of fuel cell 2 at this time. _n+1 The calculation is as follows: In this case, the ECU9 determines that the output value of the fuel cell 2 is output value A. _2 The power generation of fuel cell 2 is controlled to achieve this. At this time, the ECU 9 calculates the difference between the output value of fuel cell 2 and the instantaneous output value required by fuel cell system 1, and controls the discharge of battery 6 so as to compensate for this calculated difference with the output value (discharge) from the discharge of battery 6.

[0037] As a result, the line P in Figure 6 ave_total As shown, the output value A of fuel cell 2 is equal to the average output value P ave_total As time progresses and the length of the average calculation interval increases, it gradually approaches this value. As a result, the fuel for fuel cell 2 becomes the best.

[0038] Here, the average output value P is calculated by the ECU9. ave and motor 4 ave Here is an example of a calculation method.

[0039] [Calculation Method 1] Average output value P of fuel cell 2 ave and motor 4 aveThe calculation method involves using the average value of the average calculation time interval, the instantaneous output value required by the fuel cell system 1 during the average calculation time interval, the output value of the motor 4's current (discharge), and the input value of the motor 4 (charge) (Calculation Method 1). In this case, the ECU 9 acquires the detection result detected by the second detection unit 8, and based on the acquired detection result, calculates the instantaneous output value required by the fuel cell system 1 during the average calculation time interval, the output value of the motor 4's current (discharge), and the input value of the motor 4 (charge). Subsequently, the ECU 9 calculates the average value obtained by averaging the calculated instantaneous output value required by the fuel cell system 1 during the average calculation time interval, the output value of the motor 4's current (discharge), and the input value of the motor 4 (charge) over the average calculation time interval as the average output value P. ave It is calculated as follows.

[0040] [Calculation Method 2] Also, the average output value P of fuel cell 2 ave and motor 4 ave Another estimation method is to calculate it using the fluctuation in the State of Charge (SOC) of battery 6 before and after the average calculation time interval, and the output value A of fuel cell 2 during that average calculation time interval (Estimation Method 2).

[0041] Specifically, the ECU9 calculates the average output value P of the fuel cell 2 using the following equation (1) or (2). ave and motor 4 ave Calculate.

[0042] P ave_n =Output value A _n-1 -Battery capacity × (SOC _n -SOC _0 ) ÷ Average calculation time × k (correction factor) ... (1) M ave_n_ =Output value A _n-1 -Battery capacity × (SOC _n -SOC _0 ) ÷ Average calculation time × k (correction factor) ... (2) Note that k is a value used to compensate for charge / discharge losses or boost converter losses, etc.

[0043] Furthermore, the interval of the period added to the average calculation time interval can be changed as appropriate. The user may set it arbitrarily, it may be a fixed value, or the interval may gradually increase.

[0044] Furthermore, the ECU9 may calculate the difference between the current value of the battery 6's SOC and the target value of the battery 6's SOC, and if this difference exceeds a specified value, it may increase or decrease the power generation of the fuel cell 2's output value A to bring it closer to the target value of the battery 6's SOC. For example, if the current value of the battery 6's SOC is greater than or equal to the target value, the ECU9 will control the fuel cell 2's output value A to decrease, while if the current value of the battery 6's SOC is not greater than or equal to the target value, it will control the fuel cell 2's output value A to increase. Specifically, when the ECU9 controls the fuel cell 2's output value A to decrease, it will use the following equation (3) to calculate the output value A of the fuel cell 2. _n While calculating the output value A of the fuel cell 2, when controlling to increase the output value A of the fuel cell 2, the output value A of the fuel cell 2 is calculated using the following equation (4). _n Calculate.

[0045] Output value A _n= Output value A _n-1 -Battery capacity × (SOC _n -SOC _0 ) ÷ Average calculation time × k (correction coefficient) + α (adjustment value for SOC) ... (3) Output value A _n= Output value A _n-1 -Battery capacity × (SOC _狙い値 -SOC _0 ) ÷ Average calculation time × k (correction factor) ... (4)

[0046] Furthermore, the ECU9 may retain the last output value A of the fuel cell 2 from the previous trip of vehicle 100 and use it as the initial value for the next trip of vehicle 100. This allows the vehicle to operate from the start with an output value A of the fuel cell 2 that is close to the optimal fuel efficiency.

[0047] Alternatively, the ECU 9 may pre-calculate the initial value of the output value A of the fuel cell 2 based on the driving route set for the vehicle 100 and the amount of cargo loaded onto the vehicle 100, and set this calculated initial value of output value A.

[0048] According to Embodiment 1 described above, the ECU 9 calculates the difference between the output value of the fuel cell 2 and the instantaneous output value required by the fuel cell system 1, and controls the battery 6 to compensate for this calculated difference with the output value (discharge) due to the discharge of the battery 6. As a result, the output value A of the fuel cell 2 becomes the average output value P ave_total As time progresses and the length of the average calculation interval increases, the result gradually approaches the optimal value, thus indicating that the fuel for fuel cell 2 is the best.

[0049] (Embodiment 2) Next, Embodiment 2 will be described. In Embodiment 1, there was only one mode, but in Embodiment 2, multiple modes are provided, and the system switches to one of the multiple modes depending on the fuel cell 2, battery 6, and accelerator opening. The fuel cell system according to Embodiment 2 has the same configuration as the fuel cell system 1 according to Embodiment 1, but the processing performed by the ECU is different. The following describes the processing performed by the ECU of the fuel cell system according to Embodiment 2.

[0050] (Processing of fuel cell system 1) Figure 7 is a flowchart outlining the processes performed by the fuel cell system 1. Figure 8 is a schematic diagram showing the transition conditions in modes 1 to 3 performed by the fuel cell system 1.

[0051] As shown in Figure 7, first, the ECU 9 obtains the battery temperature of the battery 6 detected by the first detection unit 7 (step S1), and then obtains the time-averaged battery discharge amount of the battery 6 detected by the second detection unit 8 (step S2).

[0052] Next, the ECU 9 acquires the accelerator pedal opening angle that the user has pressed down on the accelerator pedal, as detected by the third detection unit 10 (step S3).

[0053] Subsequently, if the battery temperature is below the first threshold (Step S4: Yes), and the time-averaged battery discharge amount is below the second threshold (Step S5: Yes), and the access opening is below the third threshold (Step S6: Yes), the ECU 9 sets and controls the fuel cell system 1 in mode 1 (normal (control similar to Embodiment 1)) (Step S7). In this case, when the vehicle 100 is accelerating, the ECU 9 sets the output value of the battery 6 to the output value of the fuel cell 2 A from the required output value of the fuel cell system 1 (motor 4). _n The fuel cell 2 and battery 6 are controlled so that the value obtained by subtracting (a constant) is obtained (Battery 6 output value = Fuel cell system 1 required output value - Fuel cell 2 output value A). _n (Constant). Also, when the vehicle 100 is decelerating, the ECU 9 calculates the charge output value of the battery 6 and the output value of the fuel cell 2 A, which is equal to the output value of the regenerative energy of the motor 4. _n The fuel cell 2 and battery 6 are controlled so that the value obtained by adding (a constant) becomes the same (Battery 6 charging output value = Motor 4 regenerative energy output value + Fuel cell 2 output value A) _n (Constant). The first threshold, second threshold, and third threshold can be set as appropriate.

[0054] Next, the ECU9 determines whether or not a power-off instruction signal has been input from the injection switch (step S8). If the ECU9 determines that a power-off instruction signal has been input from the injection switch (step S8: Yes), the fuel cell system 1 terminates this process. On the other hand, if the ECU9 determines that no power-off instruction signal has been input from the injection switch (step S8: No), the fuel cell system 1 returns to step S1.

[0055] In step S4, if the battery temperature is not less than the first threshold value (step S4: No), or if the battery temperature is less than the first threshold value (step S4: Yes) and the time-averaged battery discharge amount is not less than the second threshold value (step S5: No), the fuel cell system 1 is set to mode 2 (battery protection mode) and controlled (step S9). After step S9, the fuel cell system 1 proceeds to step S8.

[0056] Here, mode 2 (battery protection mode) will be described. FIG. 9 is a diagram showing the relationship between the output value of the fuel cell 2, the output value (discharge) of the battery 6, the input (charge) of the battery 6, and time. In FIG. 6, the horizontal axis represents time, the positive of the vertical axis represents the output value of the fuel cell 2 and the output value of the battery 6, and the negative represents the input (charge) of the battery 6. Also, in FIG. 9, region B10 represents the input value of the battery 6 due to the regenerative energy of the motor 4, region B11 represents the output value of the battery 6, and region B12 represents the output value of the fuel cell 2.

[0057] When the output value of the fuel cell 2 is greater than the average output value P of the output value of the motor 4 ave_total (motor output value < A: average output value P ave_total ), control is performed in mode 2 to suppress or stop the power generation of the output of the fuel cell 2. In this case, the ECU 9 suppresses or stops the charging amount from the fuel cell 2 to the battery 6, and makes the charging of the battery 6 the regenerative energy from the motor 4.

[0058] In this case, as shown in Figure 9, the ECU 9 controls the discharge output of the battery 6. Specifically, the ECU 9 limits the discharge amount of the battery 6 to the amount stored by the regenerative energy from the motor 4 (see regions B10 and B11). That is, the ECU 9 gradually reduces the output value of the fuel cell 2's power generation based on the battery temperature detected by the first detection unit 7, thereby stopping the charging of the battery 6 from the fuel cell 2. In this case, in order to prevent the temperature rise due to heat generation caused by the internal resistance of the battery 6 or the deterioration of the battery 6 due to the use of high-rate discharge, the ECU 9 may estimate the ion concentration of the battery 6 based on the current and voltage values ​​detected by the second detection unit 8, and based on this estimation result, perform control to gradually reduce the output value of the fuel cell 2's power generation.

[0059] Furthermore, in Mode 2, the ECU 9 drives the fuel cell 2 to compensate for the battery 6's deficit when the battery 6 can no longer supply power commensurate with the motor 4's output because the battery 6's output and discharge amount are limited. Specifically, as shown in Figure 9, the ECU 9 drives the fuel cell 2 to compensate for the battery 6's deficit when the battery 6 can no longer supply power commensurate with the motor 4's output according to the instantaneous output value P of the fuel cell system 1 (see regions B11 and B12).

[0060] As a result, the fuel cell system 1 can maximize the extraction of regenerative energy from the motor 4 while minimizing the impact on fuel efficiency. Furthermore, the fuel cell system 1 can eliminate the heat generation and ion imbalance in the battery 6 in a short time without reducing the state of charge (SOC) of the battery 6.

[0061] Furthermore, when the ECU 9 suppresses power generation from the fuel cell 2, it records the State of Charge (SOC) of the battery 6 based on the detection result detected by the second detection unit 8, and controls the power generation of the fuel cell 2 so that this SOC value does not fall below a certain level. In this case, if the SOC value of the battery 6 falls below the second threshold, the ECU 9 controls the battery 6 to stop discharging.

[0062] In step S6, if the accelerator opening is not below the third threshold (step S6: No), the fuel cell system 1 is set to mode 3 (climbing (power)) and controlled (step S10). In this case, the ECU 9 controls the output value A of the fuel cell 2 when the vehicle 100 is accelerating. _n The fuel cell 2 and battery 6 are controlled so that the output value of the fuel cell system 1 (motor 4) is the value obtained by subtracting the maximum output value of battery 6 from the required output value of the fuel cell system 1 (output value A of fuel cell 2) _n (Constant) = Required output value of fuel cell system 1 - Maximum output value of battery 6). Also, when vehicle 100 is subtracted, ECU 9 calculates the output value A of fuel cell 2. _n The fuel cell 2 and battery 6 are controlled so that the output value obtained by subtracting the output value from the regenerative energy of the motor 4 from the maximum charge output value of the battery 6 (Fuel cell 2 output value A _n (Constant) = Maximum charge value of battery 6 - Output value due to regenerative energy of motor 4). In other words, the longer the time that the output value A of fuel cell 2 is constant, the greater the effect of improving fuel efficiency. However, when the fuel cell system 1 (motor 4) requires a high required output value, such as when climbing a hill or accelerating rapidly, and the battery 6 cannot be sufficiently charged or discharged, the vehicle 100 can be accelerated smoothly by temporarily changing the output value A of fuel cell 2. After step S10, the fuel cell system 1 moves to step S8.

[0063] According to the embodiment 2 described above, if the output value A output by the fuel cell 2 is higher than the output value due to the regenerative energy of the motor 4, the ECU 9 suppresses the output value A output by the fuel cell 2 or stops the output of the fuel cell 2. This prevents deterioration of the battery 6 and prevents a decrease in the state of charge (SOC) of the battery 6, while also improving fuel efficiency.

[0064] Furthermore, according to Embodiment 2, the ECU 9 discharges only the power charged according to the output value from the regenerative energy of the motor 4, thereby maximizing regenerative energy while minimizing the impact on fuel efficiency.

[0065] Furthermore, according to Embodiment 2, when the ECU 9 determines that the temperature of the battery 6 is not below the first threshold, it switches from Mode 1, in which the difference between the instantaneous output value of the fuel cell system 1 and the output value of the fuel cell 2 is compensated for by the output of the battery 6, to Mode 2, in which the output value of the fuel cell 2 is suppressed or the output of the fuel cell 2 is stopped, thereby controlling the fuel cell 2 and the battery 6. This makes it possible to improve fuel efficiency while preventing deterioration of the battery 6.

[0066] Furthermore, according to Embodiment 2, when the ECU 9 determines that the accelerator opening is not below a third threshold, it switches from Mode 1, in which the difference between the instantaneous output value of the fuel cell system 1 and the output value of the fuel cell 2 is compensated for by the output of the battery 6, to Mode 3, in which the difference is calculated by adding the output value of the fuel cell 2 and the output value that causes the battery 6 to discharge to its maximum, thereby controlling the fuel cell 2 and the battery 6. As a result, the vehicle 100 can accelerate smoothly even when going uphill.

[0067] (Other embodiments) In the fuel cell systems according to Embodiments 1 and 2, the term "part" as used above can be replaced with "means" or "circuit." For example, the first detection unit can be replaced with the first detection means or the first detection circuit.

[0068] Furthermore, the programs to be executed by the fuel cell systems according to Embodiments 1 and 2 are provided as installable or executable file data recorded on a computer-readable recording medium such as a CD-ROM, flexible disk (FD), CD-R, DVD (Digital Versatile Disk), USB media, or flash memory.

[0069] In this specification, the flowcharts have used expressions such as "first," "then," and "next" to indicate the sequence of processes between steps. However, the order of processes necessary to implement this embodiment is not uniquely determined by these expressions. In other words, the order of processes in the flowcharts described herein can be changed within a reasonable range.

[0070] Further effects and modifications can be readily derived by those skilled in the art. Broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents.

[0071] Although some embodiments of this application have been described in detail above with reference to the drawings, these are illustrative examples, and the present invention can be implemented in various other forms with modifications and improvements based on the knowledge of those skilled in the art, starting with the embodiments described in the disclosure section of the present invention. [Explanation of symbols]

[0072] 1 Fuel cell system; 2 Fuel cell; 3 Boost converter; 4 Motor; 5 Inverter; 6 Battery; 7 First detection unit; 8 Second detection unit; 9 ECU; 10 Third detection unit; 100 Vehicle

Claims

1. A fuel cell that generates electricity using fuel, A battery that can charge and discharge power, A power source that is driven using power output from at least one of the fuel cell and the battery, A processor that controls the power output by the fuel cell and the battery, A fuel cell system comprising, The aforementioned processor, The instantaneous output values ​​sequentially requested by the fuel cell system are averaged over the average calculation time interval during which the fuel cell system was in operation, and the average value is calculated at a predetermined period. Each time the average value is calculated, the average value is sequentially set to the output value that the fuel cell will output up to the next predetermined cycle. Each time the average value is calculated, the predetermined period is added to the average calculation time interval. The difference between the instantaneous output value and the output value is compensated for by the output value due to the discharge of the battery. The aforementioned drive source is It is a motor, The aforementioned processor, If the output value of the fuel cell is higher than the output value of the regenerative energy of the motor, the output value of the fuel cell is suppressed, or the output of the fuel cell is stopped. Fuel cell system.

2. A fuel cell system according to claim 1, The aforementioned processor, The output value discharged from the battery is set to discharge only the amount of power charged according to the output value from the regenerative energy of the motor. Fuel cell system.

3. A fuel cell system according to claim 2, The aforementioned processor, The temperature of the aforementioned battery is obtained, Determine whether the temperature of the battery is below a predetermined value. If it is determined that the battery temperature is not below a predetermined value, the system controls the fuel cell and the battery by switching from mode 1, in which the difference between the instantaneous output value and the output value is compensated for by the output of the battery, to mode 2, in which the output value output by the fuel cell is suppressed or the output of the fuel cell is stopped. Fuel cell system.

4. A fuel cell system according to claim 3, The aforementioned processor, Get the throttle opening, Determine whether the accelerator opening is less than a predetermined value. If it is determined that the accelerator opening is not less than a predetermined value, the system switches from mode 1, in which the difference between the instantaneous output value and the output value is compensated for by the output of the battery, to mode 3, in which the difference is calculated by adding the output value output by the fuel cell and the output value that causes the battery to discharge to its maximum, thereby controlling the fuel cell and the battery. Fuel cell system.

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